Some d/w sensors will even have dry contacts specifically meant for wiring in whatever open/close type thing you'd like to use, like a pressure pad.

I didn’t realize there were any that weren’t part of an alarm system/proprietary but it seems the same company makes those too.

I guess that would also be a really easy to do the opposite (if it mattered) since a reed switch triggers the action when it opens, but a leak detector when it closes. Or I guess maybe they do both.

I am curious why the leak detector is bigger if it’s a simpler device. Basically the same thing but without the reed switch right? Maybe just to make room for more battery since you actually care how big the door sensor is.

Door/window sensors usually send a signal on state change from closed to open or the other way around.

I think a leak sensor is more complicated because it needs to detect a somewhat lowered resistance between the contacts, as opposed to the door sensors that will get a fully closed/opened reed switch on activation. Detecting lower resistance with some threshold in a battery powered device that needs to sleep most of the time is probably more complicated. I would guess waking up on a pin state change is built into most microcontrollers, while measuring resistance to make it wake up requires additional components?

Ah! I guess I just assumed water closed a circuit between two probes or something. I’ve never actually used one.

The door sensors on my alarm do make it many different noises on open/close so that one must trigger on both. How cool.